F5 stock suffers worst day in more than a decade as AI spending shakes investors

F5’s logo at the entrance to F5 Tower in downtown Seattle. The company’s stock fell about 20% Wednesday after it forecast slower growth and lower margins, along with more spending on AI security. (GeekWire Photo / Todd Bishop) Shares of F5 fell about 20% on Wednesday, a day after the Seattle-based company beat Wall Street’s estimates and said it would boost spending to capitalize on expected growth in the AI security market.